Wafer container with tubular environmental control components

ABSTRACT

A wafer container utilizes a rigid polymer tubular tower with slots and a “getter” therein for absorbing and filtering moisture and vapors within the wafer container. The tower preferably utilizes a purge grommet at the base of the container and may have a check valve therein to control the flow direction of gas (including air) into and out of the container and with respect to the tower. The tower is sealingly connected with the grommet. The tower may have a getter media piece rolled in an elongate circular fashion forming or shaped as a tube and disposed within the tower and may have axially extending. The media can provide active and/or passive filtration as well as having capabilities to be recharged. Front opening wafer containers for 300 mm sized wafers generally have a pair of recesses on each of the left and right side in the inside rear of the container portions. These recesses are preferably utilized for elongate towers, such towers extending substantially from a bottom wafer position to a top wafer position. In alternative embodiment, a tubular shape of getter material is exposed within the front opening container without containment of the getter other than at the ends. The tubular getter form is preferably supported at discrete locations to maximize exposure to the internal container environment. A blocker member can selectively close the apertures. An elastomeric cap can facilitate securement of the tubular component in the container portion.

RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.12/922,408, filed Dec. 17, 2010, which will issue as U.S. Pat. No.8,783,463 on Jul. 22, 2014, which application was a National Phase entryof PCT Application No. PCT/US2009/037143, filed Mar. 13, 2009, whichclaims the benefit of U.S. Provisional Application No. 61/036,353, filedMar. 13, 2008, the disclosures of which are hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE INVENTION

Wafer containers and reticle pods generally are sealed containers knownas FOUPs (front opening unified pods), FOSBs (front opening shippingboxes), or SMIF (standard mechanical interface) pods. These containersprovide a microenvironment to isolate and control the environmentsurrounding a wafers and substrates used in manufacturing integratedcircuits, during storage, transport and processing of the materials.Processing of such materials traditionally has been carried out in aparticulate free environment generally known as a “clean room”. However,maintenance of such “clean rooms” in a contaminant free state canrequire a great deal of care and effort, particularly during processingof the materials.

The internal atmosphere of such microenvironments can be more readilycontrolled and maintained. Often, such containers are purgible withinert gas or clean dry air (CDA) or extra CDA. It has been observed thatcontamination of reticles in such containers can be caused not only bydiscrete particles but also by hazing occurring on wafers or reticles.See Publication WO 2007/149513 A2, owned by the owner of the instantapplication, which is incorporated herein by reference and included inthe Appendix to this application. Such hazing can also occur on wafersin wafer containers and be detrimental thereto, see U.S. Pat. No.5,346,518 which is incorporated herein by reference. Also relevant, U.S.Pat. No. 6,042,651, owned by the owner of the instant application,discloses using nozzled towers in bottom opening SMIF pods and a frontopening wafer container that uses wafer shelf assemblies as purgeoutlets. Problems associated with such structures and optimal use ofsuch structures has not been adequately addressed.

For example, the use of desiccants and vapor getters in substratecontainers typically require removal or disassembly of same beforewashing and such substrate containers as the fluids utilized can destroythe media for filtering and/or vapor absorption. Moreover, purge portplumbing within substrate containers is, aside from the media issues,difficult to clean and dry due to the enclosed areas used fortransferring purge gases. A means for facilitating cleaning of suchsubstrate containers without disassembly and removal of media and purgecomponents would be very advantageous. Particularly, problematic incleaning are free standing towers such as disclosed in U.S. Pat. No.6,042,651. Moreover, such towers are subject to movement and potentialdislocation due to their conventional positioning where they may beinadvertently contacted and their connection only at the base of thesubstrate container. Better positioning and attachment methods andstructures would be advantageous, particularly methods that do not relyon holes or fasteners that extend through walls or other barriersseparating the enclosed interior of the container from the exterior.

The use of discrete towers in a front opening pod, the use of more thanone discharge tower, and the optimal placement and securement ofdischarge towers or tubular environmental control components has notheretofore been adequately considered and optimized to satisfactorilyaddress reliability, haze, contamination and particulate control, andcleaning issues in front opening large diameter wafer containers. As atransition is made from 300 mm wafers to 450 mm wafers, improvements inthese areas will be even more important.

SUMMARY OF THE INVENTION

In an embodiment of the invention, a wafer container includes a tubularenvironmental control component that is configured with an open interiorand slots communicating with the interior of the wafer container. One ortwo of the tubular component may be strategically placed in back cornersor compartments of the wafer container and may be connected to purgeinlets on the bottom of the wafer container. Certain embodiments mayhave a filter in addition to or alternatively to the absorbent material.In certain embodiment an additional purge inlet port may be utilized fora total of three purge inlets. The tubular components or the purge portsmay have a check valve therein to control the flow direction of gas(including air) into and out of the container and with respect to thetower. The purge port may utilize an elastomeric grommet and the tubularcomponent sealingly connected thereto. The tubular component may have agetter media piece rolled in an elongate circular fashion forming orshaped as a tube and disposed within the tower. The media can provideactive and/or passive filtration as well as having capabilities to berecharged.

One configuration of front opening wafer containers for 300 mm sizedwafers have a pair of compartments on each of the left and right side inthe inside rear of the container portions. These compartments reflectthe interior structure formed by the pair of vertical externalprojections on the back wall of wafer containers that are utilized asfeet or seating features when the container portion is rotated rearwardninety degrees. A feature and advantage of certain embodiments isutilizing these compartments for containing, completely or partially,elongate tubular environmental control components that extendsubstantially from a bottom wafer position to a top wafer position orfrom the bottom of the container portion to the top. In one embodiment,a tubular shape of getter material is exposed within the front openingcontainer in one or both compartments with minimal containment of thegetter and without being part of an active purge system. In anotherembodiment, a tubular environmental control component configured as apurge tower may be placed in one or both compartments. The tower may beconfigured as a containment portion that may contain media. The mediacan be filter and/or absorbent media.

In particular embodiments, the tubular environmental control componenthas apertures either for exuding purge gas into the open interior of thecontainer portion or for allowing absorbent media in the component toabsorb vapors, including humidity from the interior of the containerportion. A feature and advantage is that such apertures may beselectively obstructed to stop communication between the interior of thetubular component and the open interior of the wafer container. This ishighly advantageous for washing the container so that filters, getters,or other contents of the tubular component can be protected from thewashing fluids without removing the components. The obstruction may beby an elastomeric strip that seals the apertures as by a rigid slidablyattached member that can cover and uncover the apertures. Moreover suchselective blocking can be adjustable to change the size of the openingsbetween the interior of the container portion and the interior of thetubular component.

A feature and advantage of certain embodiments is that the tubularcomponent with apertures may be horizontally offset form the purge inletconnected thereto. This provides clearance with respect to the wafers.Moreover, positioning the discharge aperture in the tubular componentback in the recess or compartment is believed to provide better fluidflow characteristics for the purge gas. Positioning the tubularcomponents in the back recess provides the advantage of protection ofthe purge component from bumping or inadvertent contact.

A feature and advantage of certain embodiments is the methods ofattachment of environmental control components in the rear compartments.These compartments reflect the interior structure formed by the pair ofvertical external projections on the back wall of wafer containers thatare utilized as feet or seating features when the container portion isrotated rearward ninety degrees. These internal compartments have wallsthat generally converge rearwardly. In a particular embodiment, aflexible elastomeric attachment member is secured intermediate the topof a tubular environmental control component and the polymer wall of thecontainer portion. Such elastomeric attachment member secures the towerin place without apertures through the walls and optimally utilizes thehigh coefficient of friction between the polycarbonate container portionwall and the elastomeric material. The member may be shaped as a capfurther providing the advantageous function of securing togetherelongate components that comprising the containment portion of tubularenvironmental control components. A tubular component may have such amember on both ends to utilize the high coefficient of friction and thecompression of the elastomeric members to retain said tubularenvironmental control component within, totally or partially, therearward compartment. In another embodiment a rigid bracket formed frommetal or a rigid polymer may have spring teeth to wedge the bracketbetween opposing walls of the compartment wherein the teeth dig into thesurface of the container portion wall. A feature and advantage of theseattachment methods and structures is that the attachment utilizes theopposing walls for engagement of the attachment components withoutseparate structure or fasteners that extend through walls of the wafercontainer. Therefore, wafer containers may be readily retrofitted withno modifications or reduced modifications to the product.

A feature and advantage of embodiments utilizing the tubular gettermedia is that a relatively high area of media is effectively exposed ina confined area in the wafer container. Moreover, the rear compartmentswork well for the tubular components that have no media and are utilizedfor pure purging.

A further feature and advantage of certain embodiments is that wherepurge gas is exhausted through the tower, the tubular getter media maybe effectively recharged for periods when the environment therein isstatic.

A further feature and advantage of embodiments herein is thataccommodation of the invention in existing configurations of 300 wafercontainers requires minimal changes in such containers. A furtherfeature and advantage is that aspects of the invention are highlysuitable for larger wafer containers.

DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a front opening wafer containeraccording to an embodiment of the invention;

FIG. 2 is a bottom view of the wafer container of FIG. 1;

FIG. 3 is a front perspective view into the open front of a differentembodiment of a container portion;

FIG. 4 is a detail top view cross-sectional of the embodiment of FIG. 3showing the location of tubular components and purge ports with respectto the walls of the container portion and wafers therein;

FIG. 5 is an elevational view of a tubular component;

FIG. 6 is a detail view of attachment features suitable for securing thetower component to the bottom wall of a container portion of a frontopening wafer container;

FIG. 7 is a front elevation view of a container portion with a pair oftubular environmental control components configured as filter cartridgesmounted therein with brackets;

FIG. 8 is a perspective view of tubular environmental control componentsconfigured as an absorbent filter cartridge according to an embodimentof the present invention;

FIG. 9 is a bracket suitable for attaching a tubular environmentalcontrol component to the back region of a wafer container such as isshown in FIGS. 4 and 5;

FIG. 10 is a top cross sectional view illustrating an attachment meansfor a tubular environmental control component of a wafer container;

FIG. 11 is a perspective view of a filter cartridge in a bracket;

FIG. 12 is a perspective view of the bracket of FIG. 11;

FIG. 13 is a cross sectional view taken at line 13-13 of FIG. 4;

FIG. 14 is an exploded view of a tubular environmental control componentaccording to an embodiment of the invention;

FIG. 15 is an exploded view of a tubular environmental control componentof the tubular environmental control component of FIG. 14;

FIG. 16 is a front side perspective view of a tubular environmentalcontrol component;

FIG. 17 is a rear side view of the tubular environmental controlcomponent of FIG. 16;

FIG. 18 is a front perspective view of the tubular environmental controlcomponent of FIGS. 16 and 17 with a blocking member engaged therewith;

FIG. 19 is a front side perspective view of a tubular environmentalcontrol component according to an embodiment of the invention;

FIG. 20 is a detail view of the tubular environmental control componentof FIG. 19 opened revealing a living hinge;

FIG. 21 is a container portion according to an embodiment of theinvention; and

FIG. 22 is a perspective view of an alternative embodiment of a blockingmember 800 according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, a front opening wafer container 20 isdepicted and generally includes door 24 and container portion 26.Container portion 26 has front opening 30 leading into open interior 32where a plurality of wafers W are retained on wafer shelves 35. Door 24has key access holes 36 with latch mechanism 38 partially illustrated inthe interior of the door enclosure with latch tips 41 that engagerecesses 39 in the container portion door frame 40. The wafer containerhas purge capabilities with a pair of forward purge ports 48 with purgegrommets 50 which are secured into grommet receiving structure 51 on thebottom 52 of the container portion and rearward purge ports 54. Checkvalves 56 may be inserted into the grommets to control the direction ofpurging gas fluid flow. Tubular environmental control componentsconfigured as purge towers 60 are illustrated which also may utilizegrommets 62 and check valves 64. An exemplary location of purge ports isillustrated in FIG. 2 with reference to the wafers W.

Referring to FIGS. 3, 4, and 13, further details of a wafer containerwith a different configuration portion 26 embodying the inventions areillustrated with appropriate component placement. The container portion26 has a shell 65 and closed top 66, a closed bottom 66.1, a closed leftside 66.2, a closed right side 66.3, an open front 67, and a closed back67.1. The interior of the container has a plurality of shelves 70 whichmay be secured to the container portion at the top and bottom of same. Akinematic coupling plate 74 (not shown in FIG. 4) is positioned at thebottom of the container portion and has appropriate openings forreceiving the front side grommets and rear side grommet 77 at rear ports54. The openings will extend through the shell 65. The container portion26 has two rearward apertures 80 which extend from the interior 32 ofthe wafer container to the exterior.

The tubular environmental control component 78 configured as a towercomponent as depicted in FIGS. 3 and 13 is inserted into the containerportion 26 from the interior into the aperture 80. The tubular componenthas a containment portion 81, an offset portion 83, and port portion 85.Elastomeric grommet 77 may be sealingly placed in the lower portion 94of the tubular component and a check valve 62 may be placed therein. Acylindrical shaped filter and/or getter media material 100 may beincluded in the containment portion and is configured to conform to theinterior of the tubular component. Said tubular component has aplurality of axially-extending apertures 110 configured as horizontalslots disclosed therein. In a preferred embodiment, there may be a slitfor each wafer with the slit position to discharge purge gas over thesurface of the respective wafer. The media material, if in thecontainment portion, is thus exposed to the interior of the wafercontainer by way of said axially-extending openings. Of particular noteof this container portion 26 is the rearward compartments 111 that aredefined by rearward protrusions 112 at the back 67.1. The wall 113 isconfigured to provide two feet 114 when the container is tipped rearward90 degrees whereby the front with door 24 is upward, such as forshipping. Each compartment 111 has a pair of sidewall portions 115, aback wall portion 116 and a compartment opening 117.

Referring to FIGS. 5 and 6, the tubular component 119 in this embodimenthas vertical slits and has a plurality of fingers 122 that extenddownwardly into the apertures 80 through the shell and kinematiccoupling plate 74. Said fingers resiliently flex radially inward andallow a secure fit in the aperture in the bottom of the containerportion. A flange 113 may facilitate proper seating of the component.

Referring to FIGS. 7-11, additional embodiments are depicted with a pairof tubular environmental control components configured as filtercartridges 200 mounted in approximately the same position, in rearward3-sided compartments 202, and configured as getters without theassociated active purge capability of the containers illustrated inFIGS. 1-4. Such cartridges may have an outer housing 210 formed of apolymer or other suitable material with media 211 positioned therein. Ina preferred embodiment the cartridge and media will be tubular shaped.Bosses 212 on the cartridge of FIG. 8 can be utilized to attach thecartridge directly to the container portion wall by way of screwsextending through the exterior wall. Alternatively the bracket 220 asillustrated in FIG. 9 and FIG. 7 may be attached to the back wall of thecontainer portion with the cartridge clamped therein.

Referring in particular to FIGS. 10, 11 and 12 a further embodiment of afilter cartridge 300 is illustrated and again has media 304 closedwithin a housing 308. The cartridge 300 is clamped within the clamp 320which has resilient catch legs 330 with tabs 322 which can bite into thewalls of the container simply by insertion therein with no furtherattachment mechanisms. Spring arms 335 secure the cartridge in thebracket.

Specific getter media which may be utilized in the cartridges and thetowers illustrated herein is disclosed in international publication no.WO 2007/149513 A2 which is incorporated herein by reference. Similarlythe methodology and system for recharging a getter that is part of apurge system within the wafer container as illustrated herein in FIGS.2, 3 and 4 are described in detail with reference primarily to a reticlepod in said publication. Said systems and methodologies and equipmentare also applicable herein and said references incorporated for thedisclosure relating directly thereto.

Referring to FIGS. 14-18, details of a tubular environmental controlcomponent 400 in accord with the inventions herein is illustrated. Thecomponent has a pair of elongate portions 402, 406 that assembletogether to form a containment portion 410 with a containment interior414. The containment portion has an axis 418 and connects to an offsetportion 422 that connects to a purge port portion 428. An elastomericgrommet 432 may fit in a grommet receiver 440. The two elongate portionsare configured as elongate clam shell portions. A rearward portion 406has edge portions 444 with latch portions 448 configured as loops. Theforward portion 402 also has edge portions 448 with latch portions 452configured as tabs to engage the loops. The latch portion operates tosecure the elongate portion together while allowing disassembly forcleaning or media placement or replacement. The forward portion 402 hasan aperture portion 451 with a plurality of apertures 453 that providecommunication between the containment interior 414 and the open interiorof the container portion.

Referring in particular to FIGS. 13-18, an elastomeric elongate blockingmember 460 is configured as a strip to engage the aperture portion byhaving tabs 464 fit into and seal the aperture 453. FIGS. 13 and 18illustrate the member 460 in a blocking position. Thus, the blockingmember can selectively block or expose the interior of the containmentportion to the interior of the container portion.

Referring still to FIGS. 13-18, an elastomeric retainer, configured asan elastomeric cap 500, resiliently expands and fits over the upper endportion 506 of the tubular component 400. The cap 500 has a dome shapeand has an extension portion 516 that is configured to engage theinterior surface 520 of the container portion at the top. The capfunctions to secure the elongate portions together and further to engageresiliently the container portion whereby the vibration of tubularcomponent and plastic to plastic contact, the plastic component portionand the shell, is minimized. The tubular component is inserted puttingthe cap under compression and the high friction between the elastomericmaterial of the cap and the hard plastic of the shell, typicallypolycarbonate, holds the tubular component in place.

Referring to FIGS. 19 and 20, another embodiment of the tubularenvironmental control component 600 is shown. The component has two clamshell portions 604, 606 that are hinged together by a living hinge 610or the like. The two shell portions may be latched with latch portions.Apertures 630 provide communication between the interior 634 of thecapsule portion or containment portion 644 and the open interior of thewafer container. The containment portion also may connect to an offsetportion 650 and then to a purge port portion 654.

Referring to FIG. 21, an embodiment of a wafer container 692 with atubular environmental control component 700 is placed in recesses 710 onthe backside wall 714 of the container portion 718. The recesses mayhave apertures positioned and spaced from the top 720 to the bottom 722.Offset portion 726 may provide communication between the containmentportion 730 and the purge port portion (not shown) positioned in theinterior. This arrangement allows the tubular environmental controlcomponents to be changed without disturbing the interior of thecontainer portion to the same level as some of the other embodiments.

Referring to FIG. 22, an alternative embodiment of a blocking member 800is illustrated. This rigid plastic, for example polycarbonate, piececlamps around a tubular environmental control component, such as theconfiguration of FIG. 19. Gripping fingers 810 may secure the member tothe tubular member by locking on to the rear corner 670 with wedge shapeteeth 812. In a further embodiment the blocking member may haveapertures 820 that correspond with the apertures 630 on the tubularcomponent. This component can then slidably engage with the tubularenvironmental control component by sliding vertically, can open, closeor adjust the communication between the interior of the tubularcomponent and the interior of the container portion. Similarly shapedrigid blocking components can have arcuate fingers that partially wraparound the tubular components with cylindrical or oval cross-sectionalshapes. The present invention may be embodied in other specific formswithout departing from the spirit of the essential attributes thereof;therefore, the illustrated embodiments should be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims rather than to the foregoing description to indicatethe scope of the invention.

The invention claimed is:
 1. A front opening wafer container comprising:a container portion having a top wall, a bottom wall, a pair of sidewalls, and back wall, the walls defining a door frame defining an openfront; a purge port defined in the bottom wall of the container portion;a door to fit in the open front and latchable to the door frame; and atleast one elongate environmental control component configured for theintroduction of gas into an interior of the container portion, theelongate environmental control component having a length extendingsubstantially a distance between the top wall and the bottom wall,wherein the elongate environmental control component has an axis that isupright and the elongate environmental control component is connected tothe bottom wall of the container portion at the purge port, the purgeport having an axis that is offset from the axis of the environmentalcontrol component.
 2. The front opening wafer container of claim 1,wherein the elongate environmental control component is comprised of twoelongate portions, each elongate portion connected by a plurality oflatches for securing the elongate portions together, the two portionsdefining a containment region.
 3. The front opening wafer container ofclaim 1, wherein the environmental control component comprises at leastone of a filtration material or a vapor absorbent material.
 4. The frontopening wafer container of claim 1, wherein the elongate environmentalcontrol component has a containment portion with an interior and aplurality of apertures providing communication between the interior ofthe containment portion and the open interior of the container portion.5. The front opening wafer container of claim 1, wherein the elongateenvironmental control component is comprised of two elongate portionsdefining a containment portion, and wherein the elongate environmentalcontrol component further comprises an elastomeric cap that resilientlyexpands to adheringly cover the top of the containment portion.
 6. Thefront opening wafer container of claim 1, further comprising anadditional elongate environmental control component and wherein the twoelongate environmental control components are both connected to a purgeport defined in the bottom wall of the container portion, and whereinthe container portion has a further outlet on the bottom wall of thecontainer portion proximate the door frame.
 7. A front opening wafercontainer comprising: a container portion having container wall thatextends around a closed left side, a closed right side, a closed bottom,a closed top, and a closed backside defining an open interior, a doorframe defining an open front, wherein the container portion wall at theback side has a pair of corner regions extending from the top of thecontainer portion to the bottom of the container portion; a door to fitin the open front and latchable to the door frame; a pair of elongateenvironmental control components configured for introducing a gas intothe open interior of the container portion, the pair of elongateenvironmental control components positioned in the corner regions,wherein each of the elongate environmental control component has an axisthat is upright and wherein each of the elongate environmental controlcomponents is connected to the bottom of the container portion at apurge port defined in the bottom closed bottom and having an axis thatis offset from the axis of the environmental control component.
 8. Thefront opening wafer container of claim 7, the pair of elongateenvironmental control are spaced from the wall portions and the backside and each of the elongate environmental control components having alength, the length extending substantially a distance between the topwall portion and the bottom wall portion.
 9. The front opening wafercontainer of claim 7, wherein each elongate environmental controlcomponent is comprised of two elongate portions, each elongate portionconnected to the other by at least one of a plurality of latches andhinges, the two portions defining a containment portion.
 10. The frontopening wafer container of claim 9, further comprising an elongateblocking member that is positionable on at least one of the elongateenvironmental control components to selectively obstruct thecommunication between the interior of the containment portion and theopen interior of the container portion.
 11. The front opening wafercontainer of claim 7, wherein the elongate environmental controlcomponents are each comprised of two elongate portions defining acontainment portion, and wherein each of the elongate-environmentalcontrol components further comprises an elastomeric cap that resilientlyexpands to adheringly cover the top of the containment portion.
 12. Thefront opening wafer container of claim 7, wherein each of the elongateenvironmental control components has therein at least one of a filtermaterial and an absorbent material.